Position sensing toothbrush

ABSTRACT

The toothbrush includes a handle portion ( 12  or  55 ) and a brushhead portion ( 14  or  57 ) with a bristle set ( 20  or  53 ) at one end of the brushhead. At least one sensor ( 16  or  56  is located either on the handle of the toothbrush or on the bristle set back plate ( 54 ) of the toothbrush. When the sensor is located on the handle of the toothbrush, the position of the brushhead is determined by a processor ( 44  or  58 ) relative to the inside or outside surfaces of the teeth on the basis of the temperature detected by the sensor, either the outside environmental temperature or the skin temperature of the user. When the sensor is located on the bristle set back plate, the determination is made on the basis of the position of the bristle set relative to the cheek of the user.

This invention relates generally to toothbrushes, and more specificallyconcerns the determination of the position of the toothbrush bristles inthe mouth, including how far the toothbrush is into the mouth, andwhether the user is brushing the inside or outside surfaces of theteeth.

Careful brushing of all the teeth in the mouth is important for gooddental health. The teeth in each region of the mouth require careful andcomplete attention. In order to accomplish this, it is helpful to givefeedback to users concerning how long a user brushes in each region ofthe mouth. This encourages the user to carefully brush all their teeth,spending sufficient time in each region. Previous arrangements fordetermining time spent in each region have utilized sensors to determinethe position of the bristle set. However, such systems have thedisadvantage of requiring a reference point or known starting positionto determine the position of the bristle set in the mouth of the user,i.e. the position of the bristles relative to the teeth.

Accordingly, it is desirable to provide reliable information back to theuser concerning the position of the bristle set in the mouth, preferablywith an inexpensive system. This will be helpful in overcomingincomplete brushing habits.

In one embodiment, the toothbrush is capable of sensing the position ofthe bristle set position and a brushhead portion thereof relative to thetooth and comprises: a toothbrush which includes a handle portion and abrushhead portion with a bristle set at one end thereof for cleaning theteeth of a user; at least one sensor located on said toothbrush suchthat it is outside the mouth when the bristle set is in position tobrush the teeth, the sensor being responsive to temperature, wherein thesensor is oriented such that it detects the temperature of the skin whenthe bristle set is in a position adjacent one of the outside or insidesurfaces of the teeth, and detects the environmental temperature outsidethe mouth when the bristle set is in a position adjacent the other ofthe outside or inside surfaces of the teeth; a processor within thetoothbrush responsive to the temperature information from the sensor fordetermining whether the bristle set is in position to brush the outsidesurfaces or inside surfaces of the teeth; and an indication systemresponsive to the processor for indicating to the user the position ofthe bristle set relative to the teeth.

In another embodiment, the toothbrush is capable of sensing the positionof the bristle set portion thereof relative to the teeth, and comprises:a toothbrush which includes a handle portion and a brushhead portion,with a bristle set at one end thereof for cleaning the teeth of a user;at least one sensor located on a back member for the bristle set forproviding orienting information of the sensor relative to the cheek ofthe user; a processor responsive to the orienting information to providean output indicating whether the bristle set is positioned adjacent theoutside surfaces of the teeth or the inside surfaces of the teeth; andan indicator system responsive to the processor for indicating to theuser whether the bristle set is in position to brush the outsidesurfaces of the teeth or the inside surfaces of the teeth.

In another embodiment, the toothbrush is capable of sensing how far atoothbrush penetrates into the mouth, and comprises: a toothbrush whichincludes a handle portion, a neck portion and a bristle set portion at adistal end of the neck portion for cleaning teeth of a user; a pluralityof light sources positioned in a sequence along the neck portion of thetoothbrush, the light sources oriented such that the relative number oflights within the mouth and outside of the mouth is indicative of theportion of the toothbrush which is in the mouth; and a receiver forreceiving light from uncovered light sources outside the mouth, whereinthe light sources are differentiated from one another by a selectedcharacteristic, where the receiver includes a system for indicating tothe user how far the toothbrush has penetrated into the mouth.

FIGS. 1 and 2 are simple elevational views for a first embodiment of atoothbrush with one and two IR sensors.

FIGS. 3-6 are simplified diagrams showing brushing coverage relative toa set of teeth.

FIGS. 7-9 are illustrations of the position of the toothbrush in auser's mouth and the direction of the IR sensor.

FIG. 10 is an elevational view of one variation of a second embodimentof the position sensor.

FIGS. 11 and 12 are brushing diagrams for the embodiment of FIG. 10.

FIGS. 13 and 14 are elevational and top views of a further variation ofthe second embodiment.

FIG. 15 is an elevational view of another variation of the secondembodiment.

FIG. 16 is an elevational view of a still further variation of thesecond embodiment.

FIG. 17 is an elevational view of yet another variation of the secondembodiment.

FIG. 18 is a schematic view of a system for determining how far thetoothbrush extends into the mouth.

FIGS. 1-9 illustrate the structure of a first embodiment of thetoothbrush described herein and the possible positions of the bristleset portion of the toothbrush in the mouth. Sensors are used on thetoothbrush handle, which is outside of the mouth during brushing, todetermine the orientation of the bristle set relative to the teeth whenthe bristle set is in the mouth in particular, whether the bristles arein position for brushing the outside surfaces of the teeth or the insidesurfaces of the teeth. In the embodiment of FIGS. 1-9, a toothbrush 10,typically a power toothbrush, which includes a handle portion 12 and abrushhead portion 14, includes at least one sensor 16 near the upper end18 of handle 12. At the distal end of brushhead 14 is a bristle set 20,fixed to a bristle plate or back member 24. Sensors 16 in the embodimentshown are IR sensors, which are responsive to temperature. FIG. 1 showsan arrangement with a single IR sensor, while FIG. 2 shows two IRsensors, approximately 180° apart. While FIGS. 1 and 2 show the sensorsin the toothbrush handle, they could be on the neck of the toothbrush,as long as the sensors remain outside of the mouth.

FIG. 7 shows the toothbrush 10 in the mouth of a user 13. FIGS. 8 and 9show a toothbrush 10 with two sensors 25 and 27 oriented so that whenbristles 26 are oriented against the outside surfaces 28 of the teeth(FIG. 9), sensor 25 is pointed away from the skin of the user toward theenvironment (arrow 32), measuring ambient temperature (72° F.), whilethe other sensor 27 is pointed toward the skin of the user (arrow 36)and will measure body temperature (98.6° F.). When toothbrush 10 ispositioned so that the bristles 25 are oriented against the insidesurfaces of the teeth (FIG. 8), sensor 25 will be pointing in thedirection of the skin (arrow 37) and sensor 27 will be pointing towardthe environment (arrow 38).

It should be understood that only one sensor can be used and stillprovide effective results, since in one orientation of the toothbrush,the sensor will read 98.6° F., while in the other orientation, thesensor will read the environment temperature, 72° F., for example. Ineither case, using two sensors or one, the temperature informationobtained by the sensor(s) is applied to microprocessor 44 (FIG. 1)within the toothbrush, wherein the microprocessor, having beenprogrammed relative to the temperatures measured by the sensors and theposition of the toothbrush, will make a determination of the position ofthe bristles. It will then send this information to a display device 42,which is typically, but not necessarily, separate from the toothbrush.The display, for instance, could be in a charger assembly for thetoothbrush. It could be on a separate display or even on the toothbrush.The system could also provide an audible indication of bristle position.In any event, the system provides an indication to the user of theorientation of the bristles relative to the teeth.

FIGS. 3-6 illustrate the regions of the mouth that can be determined(inside tooth surfaces or outside tooth surfaces) by the arrangementdiscussed above and shown in FIG. 1 or 2. FIG. 3 shows the combinedoutside surfaces 37 and inside surfaces 38.

An accelerometer or inclinometer 45 can be added to the toothbrush 10,which, with the sensors, provides an ability of the toothbrush todistinguish four zones in the mouth, in particular, left and right sidesof the mouth, and the inside and outside teeth surfaces. FIGS. 4 and 5illustrate the coverage of a 180° difference in the inclination of thebristles when brushing the regions 39 and 40 (FIG. 4), and regions 41and 42 (FIG. 5). FIG. 6 illustrates the four zones together.

Further, the chewing surfaces of the teeth can also be identified bymeans of two additional temperature sensors positioned at approximately90° to the original two temperature sensors. All of the temperature andaccelerometer/inclinometer information is provided to the microprocessor44, which determines which region of the teeth the bristles are directedtoward or against. While IR sensors have been disclosed, other sensorsand techniques could be used to detect the presence of the face asapproved to the environment. Those could include reflective ortriangular IR sensing, capacitive sensing, proximity sensing, or evensonar (acoustic distance sensor) or laser sensing.

In the particular embodiment and variations thereof FIGS. 10-18, theobject again is to determine whether the bristles and the toothbrush areoriented toward the outside or the inside surfaces of the teeth. Thesevariations accomplish the bristle position determination relative to theinterior surface of the cheek of the user. In each of the variations, asensor assembly is positioned on the bristle back plate. When brushingthe inside of the teeth, the sensor assembly will face the inside of themouth away from the cheek, while when brushing the outside surfaces ofthe teeth, the sensor assembly will face the interior surface of thecheek. The different sensor output between these two positions isprocessed to provide an indication to the user of the position of thebristles. FIGS. 11 and 12 show a toothbrush 50, with a handle 35 and abrushhead 57, positioned in a user's mouth, shown generally at 52. InFIG. 11, the bristles 53 are positioned against the inside surfaces ofthe teeth, such that the sensor 56 on the bristle back plate 54 facesthe inside of the mouth. In FIG. 12, the toothbrush 50 is oriented sothat the bristles 53 are positioned against the exterior surfaces of theteeth. In this position, the sensor 56 faces the cheek of the user.

There are several embodiment variations disclosed herein relative todifferent sensors suitable for differentiating between the bristlesfacing the mouth region or facing the cheek of the user. FIG. 10 showsone embodiment variation in which a bristle back plate 54 of thetoothbrush 50 is equipped with an infrared temperature sensor 56. Whenthe outside surfaces of the teeth are being brushed, sensor 56 willmeasure the temperature of the cheek. When brushing the inside surfacesof the teeth, sensor 56 will measure the temperature inside the mouth.Since there is a temperature difference, the two positions of thebristles can be distinguished. The measured temperature valuesdetermined by the sensor are provided to a microprocessor illustratedgenerally at 58 in the toothbrush 55, which is programmed via a look-uptable or the like to provide an indication of the position of thebristles to a display 59 which, like the embodiments described above,can be part of a separate unit, such as a charging unit. The informationis provided typically by IR (infrared) communication. The display couldalso be on the toothbrush itself or another display device apart from acharger. It could be visual, audible or other type of indication.

In the variation of FIGS. 13 and 14, bristle back plate 60 is equippedwith an optical fiber 62. The fiber 62 extends in a loop from the handle64 of toothbrush 65 through the back of the bristle set and then back tothe handle. At one end of the fiber 62, an LED 63 is mounted thatprovides light which moves through fiber 62. On the other end of thefiber is a light sensor 66 which measures the intensity of the lightcoming out of the fiber. When the outside surfaces of the teeth arebeing brushed, the optical fiber 62 will touch the cheek. Due to thischeek contact, there will be a change of the refractive index at theborder of the fiber. Some light will now escape from the fiber and thelight intensity sensed by light sensor 66 decreases compared to when thebristles are only adjacent the inside surfaces of the teeth. The sensorprovides a different value of light intensity to the toothbrushmicroprocessor, depending upon whether the inside or outside surfaces ofthe teeth are being brushed. The microprocessor provides an indicationof the position of the bristles to the user through a display or othercommunication means, as discussed above.

FIG. 15 shows another variation, in which a metal plate 70 is mounted atthe bristle back plate 72. Plate 70 is covered with a thin layer ofplastic. The capacitance of metal plate 70 changes when the metal platetouches the cheek. The capacitance of the plate can be measured by asensor. When brushing the outside surfaces of the teeth, the capacitanceof the plate will be higher due to contact with the cheek. When theinside surfaces of the teeth are being brushed, the capacitance will belower due to lack of skin contact. The capacitance sensor 72 providesthe capacitance values to a microprocessor in the toothbrush, which willthen provide an indication to the user of whether the inside or outsidesurfaces of the teeth are being brushed on a display such as disclosedabove.

Still another variation is shown in FIG. 16, wherein the bristle setback plate 80 contains an IR LED 82 and an IR detector 84. The detector84 detects light that is emitted from the LED. When the back plate ofthe bristle set is in contact with the cheek, the IR LED 82 and IRdetector 84 will be partly covered by the skin of the cheek. The lightintensity measured by the detector 84 will be low. When the insidesurface of the teeth are being brushed, the light intensity detected bythe detector will be higher. The light intensity information is providedto a microprocessor in the toothbrush, which in turn provides anindication to the user of whether the bristles are adjacent the insideor outside surfaces of the teeth. In addition, the sides of the bristleback plate can be equipped with an IR LED and detector combination 86,which will enable detection of additional toothbrush orientations.

Another variation is shown in FIG. 17. The bristle back plate 90contains a contact switch 94. When the outside surfaces of the teeth arebeing brushed, the bristle back plate will touch the cheek and switch 94will be triggered, providing an indication of the position of thebristles relative to the teeth. When the inside surfaces of the teethare being brushed, switch 94 will not be triggered. The signal (or lackthereof) from switch 94 will be processed by a microprocessor and anindication provided to the user of the position of the bristles in themouth.

FIG. 18 shows an embodiment which determines how far a toothbrush isinserted into the mouth. The toothbrush 100 is shown with a handle 105,a bristle set 107 and a plurality of LED light sources 102-102positioned along the neck 104 of the toothbrush. In this embodiment, atleast one but preferably two or more LEDs are provided. Each LED has adifferent emitting characteristic, such as a different frequency. TheLEDs produce light which is transmitted to a receiver 106. In operation,as the toothbrush is inserted into the mouth, one or more of the LEDswill be covered, eliminating that characteristic from being transmittedand received by the receiver. The receiver determines the frequencies oflight which it receives. That information is provided to amicroprocessor, typically in the receiver, which calculates how far thetoothbrush is positioned into the mouth. That information is thenprovided as a display 108, typically on the receiver. The elements onthe neck of the toothbrush could also be temperature sensors. In thisarrangement, no external light receiver is necessary.

As a variation of the embodiment of FIG. 18, at least four infraredtemperature sensors can be provided, with a 3-D accelerometer, inaddition to the LEDs (or temperature sensors) on the neck of thetoothbrush. The information from the various sensors can then beprocessed by the microprocessor to determine a specific region of themouth being brushed.

Hence, several embodiments have been disclosed which provide informationto the user concerning the position of the bristles in the mouthrelative to the teeth. This allows the user to ensure appropriatebrushing of all regions of the teeth.

Although preferred embodiments of the invention have been disclosed forpurposes of illustration, it should be understood that various changes,modifications and substitutions may be incorporated in the embodimentswithout departing from the spirit of the invention, which is defined bythe claims which follow.

1. A toothbrush capable of sensing the position of a bristle set portionthereof relative to the teeth, comprising: a toothbrush which includes ahandle portion and a brushhead portion with a bristle set at one endthereof for cleaning the teeth of a user; at least one sensor located onthe toothbrush at such a location that it is outside the mouth when thebristle set is in position to brush the teeth, the sensor beingresponsive to temperature, or other skin characteristic, wherein thesensor is oriented such that it detects the temperature of the skin whenthe bristle set is in a position adjacent one of either the outside orinside surfaces of the teeth, and detects the environmental temperatureoutside the mouth or the absence of said other skin characteristic whenthe bristle set is in a position adjacent the other of the outside orinside surfaces of the teeth; a processor within the toothbrushresponsive to the temperature information or information of the otherskin characteristic from the sensor for determining whether the bristleset is in position to brush the outside surfaces or inside surfaces ofthe teeth; and an indication system responsive to the processor forindicating to the user the position of the bristle set relative to theteeth.
 2. The toothbrush of claim 1, including two sensors approximately180° apart on the handle, each responsive to temperature and orientedsuch that when one sensor is measuring the skin temperature, the otheris measuring the temperature outside of the mouth and vice versa.
 3. Thetoothbrush of claim 1, including an accelerometer or inclinometer,wherein information from the accelerometer or inclinometer is providedto the processor which determines which side of the mouth the bristleset is located.
 4. The toothbrush of claim 1, wherein the sensors are IR(infrared) sensors.
 5. The toothbrush of claim 1, wherein the sensorsare located on the handle of the toothbrush.
 6. The toothbrush of claim1, including two additional sensors for detecting the toothbrush beingpresent relative to the teeth in the upper or lower jaws.
 7. Thetoothbrush of claim 1, wherein the toothbrush is a power toothbrush. 8.The toothbrush of claim 1, wherein the indicator system is a visualdisplay separate from the toothbrush.
 9. A toothbrush capable of sensingthe position of a bristle set portion thereof relative to the teeth,comprising: a toothbrush which includes a handle portion and a brushheadportion, with a bristle set at one end thereof for cleaning the teeth ofa user; at least one sensor located on a back member for the bristle setfor providing orienting information of the sensor relative to the cheekof the user; a processor responsive to the orienting information toprovide an output indicating whether the bristle set is positionedadjacent the outside surfaces of the teeth or the inside surfaces of theteeth; and an indicator system responsive to the processor forindicating to the user whether the bristle set is in position to brushthe outside surfaces of the teeth or the inside surfaces of the teeth.10. The toothbrush of claim 9, wherein the sensor is located on a backsurface of the bristle set.
 11. The toothbrush of claim 9, wherein thesensor is an IR temperature sensor to distinguish between the cheek andthe interior of the mouth.
 12. The toothbrush of claim 9, wherein thesensor is an optical fiber assembly which differentiates between theinterior of the mouth and the cheek by the intensity of light present ata receiver end of the optical fiber from an LED source at a transmittalend thereof.
 13. The toothbrush of claim 9, wherein the sensor includesa capacitive element and a system for sensing the capacitance thereof,wherein the capacitance of the capacitive element increases when thebristle set is close to the cheek of the user as opposed to away fromthe cheek.
 14. The toothbrush of claim 9, wherein the sensor is aninfrared LED and an infrared detector, wherein light intensity detectedby the detector will decrease as the bristle set back member comes intocontact with the cheek.
 15. The toothbrush of claim 14, includingadditional infrared LEDs and infrared detectors positioned on the backmember for determination of additional bristle set positions relative tothe teeth of the user.
 16. The toothbrush of claim 9, wherein the sensoris a switch, which is activated when the bristle set back membercontacts the cheek of the user.
 17. A toothbrush capable of sensing howfar a toothbrush penetrates into the mouth, comprising: a toothbrush,which includes a handle portion, a neck portion and a bristle setportion at a distal end of the neck portion for cleaning teeth of auser; a plurality of sensor members positioned in sequence along theneck portion of the toothbrush, the sensor members oriented such thatthe relative number of sensor members within the mouth and outside ofthe mouth is indicative of the portion of the toothbrush which is in themouth; and a receiver for receiving information from uncovered sensormembers outside of the mouth, wherein the receiver includes a system forindicating to the user how far the toothbrush has penetrated into themouth from the sensor information.
 18. The toothbrush of claim 17,wherein the sensor members are light sources, and the receiver isadapted to receive light from uncovered light sources, wherein the lightsources are differentiated from one another by a selected characteristic19. The toothbrush of claim 17, wherein the selected characteristic isfrequency, such that the light sources emit different colored light. 20.The toothbrush of claim 19, wherein the light sources are infrared LEDs,each having a different emitting frequency.
 21. The toothbrush of claim17, wherein the sensor members are temperature sensors.